1. Field of the Invention
The invention relates to a charging device and a charging method and, more particularly, to a charging device that includes electric power supply means for supplying electric power for charging a storage battery equipped for a vehicle.
2. Description of the Related Art
In recent years, for the purpose of reduction in CO2, or the like, a hybrid vehicle that is equipped with a storage battery and that uses an engine and a motor as power sources is widely used, and an electric vehicle that is equipped with a storage battery and that uses only a motor as a power source also becomes a focus of attention. In addition, the storage battery in the hybrid vehicle is charged mainly with electric power generated by the engine; however, for the purpose of further reduction of CO2, a hybrid vehicle (so-called plug-in hybrid vehicle) in which a storage battery is chargeable even by electric power of an external power supply, such as a commercial power supply supplied from a power company to a house, or the like, is scheduled to be released, and a charging facility has not become widespread as an infrastructure for an electric vehicle as well, so it has been studied that a storage battery is designed to be chargeable with a commercial power supply, or the like, supplied to a house, or the like.
However, currently, it takes a longer time to charge a storage battery of a motor-powered vehicle, such as a hybrid vehicle and an electric vehicle, than to refuel an ordinary vehicle that uses only an engine as a power source. Therefore, it is highly likely that a user leaves the vehicle while the storage battery is being charged, and it is presumable that charging is stopped before the storage battery is fully charged and then the vehicle is used by the user again. For this reason, it may be necessary to notify the user who is away from the vehicle (for example, in a house) of a time required to complete charging the storage battery, a distance by which the vehicle can travel with a current state of charge of the storage battery, and the like.
In connection with the above, Japanese Patent Application Publication No. 5-137211 (JP-A-5-137211) describes an electric vehicle that has a function of indicating a discharge capacity and a regenerative charge capacity after a last charge, a self-discharge amount caused by a standing time, a temperature of the battery, and a distance-to-empty using a discharge capacity to be discharged before the voltage reaches a last lower limit setting voltage as a dischargeable upper limit capacity.
In addition, Japanese Patent No. 3554057 describes a technique that, when estimated riding time is specified and then charging is instructed, a required charging period of time is computed on the basis of a discharge amount of an electric vehicle storage battery at the time when charging is instructed, a detected power supply voltage and a predetermined charge current, a charge starting time for completing charging at the estimated riding time is computed on the basis of the specified estimated riding time and the computed required charging period of time, and then charging is started from the computed charge starting time.
The techniques described in the above JP-A-5-137211 and Japanese Patent No. 3554057 each are supposed to measure a charge and discharge capacity, or the like, of the storage battery. In order to notify the user of the state of charge, or the like, of the storage battery by a charging device installed at a location, such as a house, remote from the vehicle using these techniques, it is necessary to transmit the measured charge and discharge capacity, or the like, of the storage battery from the vehicle to the charging device. However, the existing specifications of a charging cable used to charge a storage battery of a vehicle do not assume an exchange of information between the vehicle and the charging device, so it is necessary to additionally provide communication means for exchanging information, such as the measured charge and discharge capacity of the storage battery, between the vehicle and the charging device. This leads to a complicated system configuration.